Process of forming composite screws or bolts



Parenteel July s, 192e.

:UNIT-Ep STATESl WILLIAM It. WILEY, or MoUNT cLEMENs, MICHIGAN, AssIeNoa To cm1: I..

BItAcxnTT, or DETROIT, MICHIGAN. i

. PROCESS OIF FORMING COMPOSITE SCREWS 0R IBOIATS.

application mea June 30,1924'. seria; Nt. 723,211. i

This invention relates to an improved process for correlating a relatively hard insert or slug with a bolt head whose component metal is of considerably lessV hard-- ness, and has for its object the roduction of such an article, as for examp e a tappet bolt, in whose lon itudinally bored top end such a slug has een placed at the commencement of the operation about to be de- Experience has Shown this special and lo-V calized hardening to be at. best a very eX- pensive and intricate operatiomwhose most careful vand scrupulous performance still leaves a high percentage of rejections of the completed articles to beexpected. i

In the drawings: t

. Figure 1 isa sectional elevational view of the bolt and its inserted slug in position of first assemblage relatively to punch member.

Figure 2 is a similar sectional elevation showing the punch member descending upon the die and the slug iwith. the resultant seating of the slug in the bottom of the bore as well as the (initial movement of the/bolt through the Figure 3 shows the next step inthe vprocess, with the bolt well on its way through the. die.

Figure 4 shows the bolt with its head still in the die but so far advanced therethrough that the compression action' on the head is 'about completed.v

Figure 5 is an velevational view of a completed boltwith the position of the hard slug indicated indotted lines.

In carrying out' my invention, I provide a die member A-, whose forming aperture B is of very slightly less diameter, at the most a few thousandths of an inch, than the diameter of the head D' of the stem member` C. In the head D there has been previously 4will be observed from inspection of Figures 1 and 2 particularly, the sides of the bore F are preferably very slightly inclined, so that so far as manual insertion of the slug Eis concerned, it can not be pushed clear to the bottom of the depression. With these parts positioned as thus .described and as illustrated in Figure 1, the slug E is subjected to the very forcible impact of the punch G; part of the effect of this stroke is to drive the'slug E farther into the bore F, but a very appreciable proportion of its driving force is communicated to the body ofthe bolt G, to effect. its lengthwise or downward movement through the aperture B of the die A. In view of the dies smaller dlametrical size above remarked u on, this can only take place resultant uponV t e correthe soft metal sides of the bor'e F with the sides of the inserted slu E, that when the bolt emerges from .the d1e the slug is structurally integral therewith. Of course the impact ofthe die G on the slug and its tappet head is of such exceedingly momentary' duration that a high rate of roduction can be easily attained, but in so ar as the various forming steps in its path of travel can be illustrated, Figures 1, 2, 3 and 4 show successive steps in this operation.

What I clalm is:

1. The process of securing a relatively hard slug in the hollowed-out central portion of the top of a bolt of relatively soft metal, consisting in subjecting the slug when positioned therein to longitudinally applied impact coincidently with, and to resultantly effect, the passage of the head of'the bolt through a die assage of slightly less diameter, thereby eecting an inward flowing of the component metal thereof into hol ing engagement of the slug by the sides of its central bore.

2. The process of effectin the structural' correlation of afrelativelyv ard slug ina terminally positioned recess'in a bolt head of markedly greater external diameter and sponding centripetal` yielding ofthe relawhose component metal is relatively softer,

consisting in positioning the bolt head with its lloosely inserted slugin a die having a movement of the relatively soft metal of the bottomless bore of very slightly smaller dilbolt head intopositive holding engagement ameter than that of the bolt head, and effect. with the sides of the initially loosely posi- 10 ing the driving of the same completely theretioned slug.

- 5 through by impact of a coexlally moving'A lIn testimony whereof, lI sign'this specidie element upon the exposed top of the slng, fication.

thereby eeting e. oentripetallyl flowed WILLIAM R. 

